Technical Details of Surgical Treatment of a Severely Displaced Sternal Fracture

Sternal fracture is an uncommon injury, which is managed conservatively in most patients. In case of failure of non-surgical management or severely displaced fractures, open reduction and internal fixation should be considered. In this case report, we present the technical details of open reduction and internal fixation for a severely displaced sternal fracture in a bicyclist. The sternal fracture was successfully treated, and the patient benefited from the rapid control of symptoms, early mobilization, and good cosmetic outcome. Conclusion: Open surgical treatment of a sternal fracture, when indicated, can be performed safely, with rapid control of symptoms, low risk of non-union, and good cosmetic outcome.


INTRODUCTION
The most common cause of sternal fracture is direct blunt trauma to the anterior chest wall in motor vehicle accidents (1,2). Sternal fracture is an uncommon injury (1), which is usually associated with other chest injuries, such as myocardial contusion, cardiac rupture, cardiac tamponade, pulmonary contusion, hemopneumothorax, and spinal injuries (1,2). Chest pain aggravated by breathing and coughing, and localized tenderness is the most common clinical manifestations (2).
The diagnosis of sternal fracture is mainly made by history taking, physical examination, plain lateral chest Xray, or chest CT scan when indicated (1, 2). After ruling out or stabilizing the associated injuries, the majority of patients, including those with non-displaced or mildly displaced fractures, are managed conservatively by painkillers, mucolytics, and chest physiotherapy (2).
Patients with moderate to severe displacement may require surgical interventions for the management of their symptoms or cosmetic problems (3).

CASE SUMMARIES
A 31-year-old male bicyclist fell off his bicycle and fractured his sternum severely. There were no associated injuries other than some facial bruises and a mild rightsided hemothorax, which was not treated in his first hospital admission. He had been discharged from the hospital and recommended to only use painkillers and wait for the spontaneous union of the fractured sternum.     The open surgical treatment was recommended to the patient and he consented to undergo surgery. The procedure was initiated with a midline incision over the upper two-thirds of the sternum. The pectoralis major muscles were dissected laterally to expose the sternum.
The fracture line was identified right below the angle of Louis. There was a two-week-old callus, which was first resected. The space behind the sternum was then bluntly dissected with a finger through the suprasternal notch. asked for plate and screw removal. The chest X-rays showed a well-healed sternum ( Figure 4). Accordingly, the two plates and 12 screws were removed. Overall, the postoperative course was uneventful. He was also in good condition three years after the first surgery.  (5). However, internal fixation by plates and screws not only allows for earlier mobilization but also leads to a more rapid and better control of patients' symptoms (6,7). There are different types of plates, which have been used and reported in the literature (3,4,7). We do not believe that the outcomes of surgery would be significantly different by using different types as long as the fracture is reduced perfectly and fixed tightly. Nonetheless, some technical issues should be kept in mind for better outcome.
If the callus is developed, it must be resected until reaching the fresh bleeding edge of the bone (7).
Vascularization of the sternum should also be protected by minimal dissection and preservation of internal mammary vessels (4). Moreover, the reduction of fractured ends must be as accurate as possible, and any bone defect should be managed by bone grafts (8). For optimal reduction, it may be necessary to resect the costal cartilage, resect the wedge of the normal bone at one side, use tapes or bone clips for traction, and have the patient in a full-paralyzed anesthetic state (3). We preferred two parallel plates with three holes on each side to achieve better fixation and avoid interference with a possible median sternotomy in the future. Also, screws should be precisely selected for each hole, based on the thickness of the bone.
When there are no concerns about vascular injuries behind the sternum, bicortical screws are preferred due to their biomechanical advantage in providing better stabilization. However, we must always shield the posterior segment by a malleable retractor or surgeon's finger. We preferred the latter in this study because the surgeon could feel the tip of the screw right after it egressed the posterior plate.
In conclusion, accurate open surgical treatment of a sternal fracture, if indicated, can lead to early mobilization, rapid control of symptoms, early return to work, lower risk of non-union, and good cosmetic outcome.